Build: workflows cache gradle wrapper

[XN137]

this avoids downloading the gradle distribution on every workflow run

also follows the recommended usage pattern for the github action:
https://github.com/actions/cache/blob/main/examples.md#java---gradle

the folder contents are deterministic:

chris@xanadu:~/code/iceberg$ tree -L 5 ~/.gradle/wrapper
/home/chris/.gradle/wrapper
└── dists
    └── gradle-7.4-bin
        └── c0gwcg53nkjbqw7r0h0umtfvt
            ├── gradle-7.4
            │   ├── bin
            │   ├── init.d
            │   ├── lib
            │   ├── LICENSE
            │   ├── NOTICE
            │   └── README
            ├── gradle-7.4-bin.zip
            ├── gradle-7.4-bin.zip.lck
            └── gradle-7.4-bin.zip.ok

7 directories, 6 files

chris@xanadu:~/code/iceberg$ rm -rf ~/.gradle/wrapper

chris@xanadu:~/code/iceberg$ ./gradlew tasks >/dev/null; echo $?
0

chris@xanadu:~/code/iceberg$ tree -L 5 ~/.gradle/wrapper
/home/chris/.gradle/wrapper
└── dists
    └── gradle-7.4-bin
        └── c0gwcg53nkjbqw7r0h0umtfvt
            ├── gradle-7.4
            │   ├── bin
            │   ├── init.d
            │   ├── lib
            │   ├── LICENSE
            │   ├── NOTICE
            │   └── README
            ├── gradle-7.4-bin.zip
            ├── gradle-7.4-bin.zip.lck
            └── gradle-7.4-bin.zip.ok

7 directories, 6 files

[rdblue]

Looks good to me when tests are passing.

[nastra]

Failed spark test looks rather unrelated

org.apache.iceberg.spark.actions.TestRemoveOrphanFilesAction3 > orphanedFileRemovedWithParallelTasks FAILED
    java.lang.AssertionError: Should delete 4 files expected:<4> but was:<3>
        at org.junit.Assert.fail(Assert.java:89)
        at org.junit.Assert.failNotEquals(Assert.java:835)

[XN137]

Tests seem to be passing, so should this be merged?

[XN137]

rebased due to merge conflict

[snazy]

LGTM

[XN137]

rebased in case we still want to do t his

[XN137]

note that these alternatives exist:
https://github.com/actions/setup-java#caching-packages-dependencies
https://github.com/gradle/gradle-build-action